The immunochemical identification of a thiol-protein disulfide oxidoreductase (glutathione-insulin transhydrogenase) in pancreatic islets.
Pancreatic islets contained insulin-degrading activity that was completely removed by antisera to purified microsomal thiol-protein disulfide oxidoreductase from rat liver. In Ouchterlony double-diffusion experiments with these antisera, extracts of islet homogenates showed a single precipitation band of identity with the purified liver enzyme. Two dimensional immunoelectrophoresis also gave a single precipitate peak like that of the liver enzyme. The concentration of the enzyme in rat islets as determined by quantitation of the precipitates obtained in the electroimmunodiffusion analysis was in the order of 1.0% of total islet protein. The results suggest that, in vitro, cleavage of insulin into its polypeptide chains is catalyzed by the thiol-protein disulfide oxidoreductase. This enzyme promoting thiol-protein disulfide inter-change may be important for regulating the content of pancreatic insulin.
D000818:Animals; D005260:Female; D005779:Immunodiffusion; D007122:Immunoelectrophoresis; D007515:Islets of Langerhans / Q000201:enzymology*; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology; D010088:Oxidoreductases / Q000032:analysis*; D011490:Protein Disulfide Reductase (Glutathione) / Q000032:analysis*; D011817:Rabbits; D051381:Rats
D010088:Oxidoreductases; D011490:Protein Disulfide Reductase (Glutathione)